Simulation of bolted joint

could anyone explain boundary conditions to represent bolts. I want to simulate housing conncected to vehicle frame with 4 bolts. vehicle frame geometry is not available. wnats to design size of bolts and forces on bolt .

there are different Options available , Fixing cylindrical holes in all directions , using fixed hinge Options ... wants to know most correct Option

Not quite sure what you are trying to do, but generally bolted connections won't load the holes, as it is the friction forces or tension in the bolts that bear the load, not shear.

Simulating bolted connections in FEM is not trivial, many factors (pre-tension, friction coefficients etc.) may influence the setup. Some FEM-programs have special functions for this type of calculations, not sure about SW sim.